Classically, hospital patient monitoring systems have involved the use of patient sensors connected to local signal processors powered by standard power mains (115 volts AC) and connected via communications cables to a central system for display. Typically, such displays have been medical cardioscopes and other specialized displays.
One of the major limitations on such systems is the need of each patient station to provide absolute isolation between the 115 volt AC supply and the patient to whom a few microamperes of leakage current may prove fatal. Extensive patient isolation apparatus has therefore been absolutely mandatary for each bed.
One of the other limitations is the specialized displays being expensive, are usually available only at the patient monitoring station where they are grouped for monitoring by one or more attendants. An alarm condition of one of several patients is difficult to visually and audably isolate and in general is extremely difficult to monitor effectively.
A number of patents illustrate systems of the above type. Representative are:
______________________________________ 3,690,312 B. H. Weppner et al Sept. 12, 1972 3,779,237 R. R. Goelte et al Dec. 18, 1973 3,536,062 A. J. Horn Oct. 27, 1970 3,545,429 E. R. Penta et al Dec. 8, 1970 3,584,618 C. J. Reinhard et al June 5, 1971 ______________________________________
Certain patents have disclosed the use of radio frequency links in patient telemetry systems either between the patient and a local antenna or between the patient and a central monitoring station.
Such patents are:
______________________________________ 3,638,642 A. E. Heflin Sr. Feb. 1, 1972 3,646,606 R. L. Buxton et al Feb. 29, 1972 3,603,881 W. E. Thornton Sept. 7, 1971 3,639,907 W. Greatbach Feb. 1, 1972 ______________________________________
A patent disclosing the use of conventional commercial television sets for display of patient monitoring data is:
______________________________________ 3,530,236 A. R. Marko Sept. 22, 1970. ______________________________________
It has also been proposed in one publication, namely Biophysical Measurements, by Peter Strong, published in November, 1970 by Tectronix, Inc. that low cost television sets may be employed for display of patient data throughout a hospital. It was suggested therein that an alarm condition could be made to trigger a recorder to produce a permanent record of the patient data.